Author: alastairporter

We had an in-person meeting at the MTG during the MetaBrainz summit to discuss the status and future of AcousticBrainz. We came up with a rough outline of things that we want to work on over the next year or so. This is a small list of tasks that we think will have a good impact on the image of AcousticBrainz and encourage people to use our data more.

State of AcousticBrainz

AcousticBrainz has a huge database of submissions (over 10 million now, thanks everyone!), but we are currently not using the wealth of data to our advantage. For the last year we’ve not had a core developer from MetaBrainz or MTG working on existing or new features in AcousticBrainz. However, we now have:

Philip, who is starting a PhD at MTG, focused on some of the algorithms/data going into AcousticBrainz

Alastair, who now has more time to put towards management of the project

Because of this, we’re glad to present an outline of our next tasks for AcousticBrainz:

Short-term

Some small tasks that are quick to finish and we can use to show off uses of the data in AcousticBrainz

Merge Philip’s similarity, including an API endpoint

Philip’s masters thesis project from last year uses PostgreSQL search to find acoustically similar recordings to a target recording. This uses the features in AcousticBrainz. We need to ensure that PostgreSQL can handle the scale of data that we have.

An extension of this work is to use the similarity to allow us to remove bad duplicate submissions (we can take all recordings with the same MBID and see if they are similar to each other, if one is not similar we can assume that it’s not actually the same as the other duplicates, and mark it as bad). We want to make these results available via an API too, so that others can check this information as well.

Merge Existing PRs

We have many great PRs from various people which Alastair didn’t merge over the last year. We’re going to spend some time getting these patches merged to show that we’re open to contributions!

Publish our Existing models

In research at MTG we’ve come up with a few more detailed genre models based on tag/genre data that we’ve collected from a number of sources. We believe that these models can be more useful that the current genre models that we have. The AcousticBrainz infrastructure supports adding new models easily, so we should spend some time integrating these. There are a few tasks that need to be done to make sure that these work

Ensure that high-level dumps will dump this new data (If we have an existing high-level dump we need to make a new one including the new data)

Ensure that we compute high-level data for all old submissions (we currently don’t have a system to go back and compute high-level data for old submissions with a new model, the high-level extractor has to be improved to support this)

Update/fix some pages

We have a number of issues reported about unclear text on some pages and grammar that we can improve. Especially important are

Front page (Show off what we have in the project in more detail, instead of just a wall of text)

Data page (instead of just showing tables of data, try and work out a better way of presenting the information that we have)

Fix Picard plugin

When AB was down during our migration we were serving HTML from our API pages, which caused Picard to crash if the AB plugin was enabled while trying to get AB data. This should be an easy fix in the Picard plugin.

High Impact

These are tasks that we want to complete first, that we know will have a high impact on the quality of the data that we produce.

Frame-level data

We want to extract and store more detailed information about our recordings. This relies on working being done in MTG to develop a new extractor to allow us to get more detailed information. It will also give us other improvements to data that we have in AB that we know is bad. This data is much bigger than our current data when stored in JSON (hundreds of times larger), so we need to develop a more efficient way of storing submissions. This could involve storing the data in a well-known binary data exchange format. A bunch of subtasks for this project:

Finish the essentia extractor software

Decide on how to store items on the server (file format, store on disk instead of database)

Work out a way to deal with features from two versions of the extractor (do we keep accepting old data? What happens if someone requests data for a recording for which we have the old extractor data but not the new one?)

Upgrade clients to support this (Change to HTTPS, change to the new API URL structure, ensure that clients check before submission if they’re the latest version, work out how to compress data or perform a duplicate check before submission)

Deduplication (If we have much larger data files, don’t bother storing 200 copies for a single Beatles song if we find that we already have 5-10 submissions that are all the same)

MusicBrainz Metadata

Rashi’s GSoC project in 2018 helped us to replicate parts of the MusicBrainz database into AcousticBrainz. This allows us to do amazing things like keep up-to-date information about MBID redirects, and do search/browse/filtering of data based on relationships such as Artists just by making a simple database query. We want to merge this work and start using it.

Dumps

When we changed the database architecture of AcousticBrainz in 2015 we stopped making data dumps, making people rely on using the API to retrieve data. This is not scalable, and many people have asked for this data. We want to fix all of the outstanding issues that we’ve found in the current dumps system and start producing periodic dumps for people to download.

Build more models

In addition to the existing models that we’ve already built (see above, “Publish our Existing models”), we have been collecting a lot of metadata that we could use to make even more high-level models which we think will have a value in the community. Build these models and publicly release them, using our current machine learning framework.

Wishlist

These are tasks that we want to complete that will show off the data that we have in AcousticBrainz and allow us to do more things with the data, but should come after the high-impact tasks.

Expose AB data on MusicBrainz

As part of the process to cross-pollinate the brainz’s, we want to be able to show a small subset of AB data that we trust on the MB website. This could include information such as BPM, Key, and results from some of our high-level models.

Improve music playback

On the detail page for recordings we currently have a simple YouTube player which tries to find a recording by doing text search. We want to improve the reliability and functionality of this player to include other playback services and take advantage of metadata that we already have in the MusicBrainz database.

Scikit-learn models

The future of machine learning is moving towards deep learning, and our current high-level infrastructure written in the custom Gaia project by MTG is preventing us from integrating improved machine learning algorithms to the data that we have. We would like to rewrite the training/evaluation process using scikit-learn, which is a well known Python library for general machine learning tasks. This will make it easier for us to take advantage of improvements in machine learning, and also make our environment more approachable to people outside the MusicBrainz community.

Dataset editor improvements

Part of the high-level/machine learning process involves making datasets that can be used to train models. We have a basic tool for building datasets, however it is difficult to use for making large datasets. We should look into ways of making this tool more useful for people who want to contribute datasets to AcousticBrainz.

Search

With the integration of the MusicBrainz database into AcousticBrainz, we will be able to let people search for metadata related to items which we know only exist in AcousticBrainz. We think that this is a good way for people to explore the data, and also for people to make new datasets (see above). We also want to provide a way that lets people search for feature data in the database (e.g. “all recordings in the key of Am, between 100 and 110BPM”).

API updates

As part of the 2018 MetaBrainz summit we decided to unify the structure of the APIs, including root path and versioning. We should make AcousticBrainz follow this common plan, while also supporting clients who still access the current API.

We should become more in-line with the MetaBrainz policy of API access, including user-agent reporting, rate limiting, and API key use.

Request specific data

Many services who use the API only need a very small bit of information from a specific recording, and so it’s often not efficient to return the entire low-level or high-level JSON document. It would be nice for clients to be able to request a specific field(s) for a recording. This ties in with the “Expose AcousticBrainz data on MusicBrainz” task above.

Everything else

Fix all our bugs and make AcousticBrainz an amazing open tool for MIR research.

Thanks for reading! If you have any ideas or requests for us to work on next please leave a comment here or on the forums.

It’s been over a year since we last posted about AcousticBrainz, but a lot of work has been going on in the background. This post will give an overview about some of the things that we’ve achieved in the last year.

Data contributions

Our last blog post was neatly titled “What do 650,000 audio files look like, anyway?” Back then, we thought that this was a lot of submissions. Little did we know… I’m glad to report that we now have over 3.5 million submissions, of which almost 2 million are for unique MBIDs. This is a great contribution and we’d like to thank everyone who submitted data to us.

Dataset and model building

MusicBrainz coder Gentlecat returned to participate in Google Summer of Code last year and developed a new tool to let us create datasets and create new computational models. We’re really excited about how this can allow community members to help us increase the quality of the semantic information we provide in AcousticBrainz. We will make another blog post soon explaining how it works.

We presented an academic overview of AcousticBrainz (PDF) at the 16th International Society for Music Information Retrieval (ISMIR) conference in Malaga, Spain. The feedback from the academic community was very encouraging. Many people were interested in the data and wanted to know what they could do with it. We hope that there will be some new projects announced using the data at this year’s conference.

Integration with other data sources

MusicBrainz and AcousticBrainz don’t exist in a vacuum. One important thing that we need to make sure we do is interact with other researchers and products in the same field. To that end, we started AcousticBrainz Labs, a showcase of some of the experiments that we’re working on in AcousticBrainz. The first thing we have published is a mapping between AcousticBrainz and the Million Song Dataset, that we hope people will use to compare these two datasets.

Database upgrades and Data format changes

We’ve just upgraded to PostgreSQL 9.5 (from 9.3), which allows us to use the new jsonb datatype introduced in PostgreSQL 9.4. This change lets us store feature data more efficiently. We also made some changes to the database schema to let us start creating new data from datasets and computation models.

One result of this is that we are creating a new complete data dump, and stopping the old incremental dumps. We are also taking the opportunity to automate this incremental dump process, which is something that a number of people have asked for.

Another change is that the format of the high level JSON data is changing. This is to better reflect some of the complexities that exist in hosting such a large and varied dataset.

Contribute to AcousticBrainz development

We’re always interested in help from other people to contribute data, code, and ideas to AcousticBrainz. Once again, MetaBrainz is participating in Google’s Summer of Code, and AcousticBrainz is a possible project to work on. If you’re not a student you’re still welcome to work with us.

Hot on the heels of our release of the first 650,000 feature files as part of the first release of AcousticBrainz, we are presenting some initial findings based on this dataset.

We thank Emilia Gómez (@emiliagogu), an Associate Professor and Senior Researcher at the Music Technology Group at Universitat Pompeu Fabra for doing this analysis and sharing her results with us. All of these results are based on data automatically computed by our Essentia audio analysis system. Nothing was decided by people. Isn’t that cool?

The MTG recently started the AcousticBrainz http://acousticbrainz.org/ project, in collaboration with MusicBrainz. Data collection started on September 10th, 2014, and since then a total of 656,471 tracks (488,658 unique ones) have been described with essentia. I have been working for a while with audio descriptors and I followed the porting some of my algorithms to essentia, especially chroma features and key estimation. For that reason, I was curious to get a look this data. I present here some basic statistics. I computed them with the SPSS statistical software.

WHICH KIND OF MUSICAL GENRES DO WE HAVE IN THE COLLECTION?

In order to characterize this dataset, I first thought about genre. In essentia, there are four different genre models: trained on the data by Tzanetakis (2001), another one compiled at the MTG (Rosamerica), Dortmund and a database of Electronic music. Far from providing information on the kind of musical genres, these models seem to be contradictory! For example, in the Tzanetakis dataset “jazz” seems to be the most estimated genre, while the proportion of jazz excerpts is very small in the other models.

Genre estimations using the Tzanetakis datasetGenre estimations using the Rosamerica datasetGenre estimations using the Dortmund datasetGenre estimations using the Electronic dataset

So in conclusion, we have a lot of jazz (according to the Tzanetakis dataset), electronic music (according to the Dortmund dataset), ambient (according to electronic dataset) and an equal distribution of all generes Rosamerica dataset (which does not include a category for electronic music)….Not very clarifying then! This is definitely something that we will be looking at in more depth.

WHAT ABOUT MOOD THEN?

For Mood characterization, 5 different binary models were trained and computed on the dataset. We observe that there is a larger proportion of non-­acoustic music, non-aggressive, and electronic. It is nice to see that most of the music is not happy and not sad! From this and previous study, I would then conclude that there is a tendency in the AcousticBrazinz dataset for electronic music.

The amount of electronic music (compare with the acoustic graph above)

…and if the music is happy or not

If we check for genre vs mood interactions, there are some interesting findings. We find that Classical is the most acoustic genre and rock is the least acoustic genre (due to its inclusion of electronic instruments):

How much music in each genre is accoustic or not

HOW IS KEY ESTIMATION WORKING?

From a global statistical analysis, we observe that major and minor modes are both represented, and that the most frequent key is F minor / Ab Major or F# minor / A Major. This seems a little strange; A major and E major are very frequent keys in rock music. Maybe there are some issues with this data that need to be looked at.

The keys and modes of the tracks in the database

IS THERE A LINK BETWEEN FEATURES AND GENRE?

I wanted to do some plots on acoustic features vs genres. For example, we observe a small loudness level for classical (cla) music and jazz (jaz), and a high one for dance (dan), hip hop (hip), pop, and rock (roc).

The loudness of songs by genre

Finally, it is nice to see the relation between equal-­tempered deviation and musical genre. This descriptor measures the deviation of spectral peaks with respect to equal-­tempered tuning. It’s a very low-­level feature but it seems to be related to genre. It is lower for classical music than for other musical genres.

Variation from equal‐tempered tuning per genre

We also observe that for electronic music, equal tempered deviation is higher than for non-­electronic music/acoustic music. What does this mean? In simple terms, it seems that electronic music tends to ignore the rules of what it means to be “in tune” more than what we might term “more traditional” music.

Variation from equal­‐tempered tuning for songs reported as electronic/non-electronic

IS THERE A LINK BETWEEN FEATURES AND YEAR?

I was curious to check for historical evolution in some acoustic features. Here are some nice plots on the evolution of number of pieces per year, and some of the most relevant acoustic features. We first observe that most of the pieces belong to the period from 1990’s to nowadays. This may be an artifact of the people who have submitted data to AcousticBrainz, and also of the data that we find in MusicBrainz. We hope that this distribution will spread out as we get more and more tracks.

Distribution of release year for the dataset. 0 represents an unknown year

There does not seem to be a large change of acoustic features as year changes. This is definitely something to look into further to see if any of the changes are statistically significant.

Are the loudness wars true? Can you see a trend?Is music getting faster? It doesn’t look like itSongs aren’t geting more complex

We have many more ideas of ways to look at this data, and hope that it will show us some interesting things that we may not have guessed from just listening to it. If you would like to see any other statistics, please let us know! You can download the whole dataset to perform your own analysis at http://acousticbrainz.org/download

What is AcousticBrainz?
The AcousticBrainz project aims to crowd source acoustic information for all of the music in the world and make it available to the public. The goal of AcousticBrainz is to provide music technology researchers and open source hackers with a massive database of information about music.

AcousticBrainz uses a state of the art research project called Essentia (http://essentia.upf.edu/), developed over the last 10 years at the Music Technology Group.

Data generated from processing audio files with Essentia is collected by the AcousticBrainz project and made available to the public under the CC0 license (public domain). In 6 weeks since its inception, AcousticBrainz contributors have already submitted data for 650,000 audio tracks using pre-release software.

Today we are releasing client programs to submit data to the AcousticBrainz server and our first public release containing audio features for over 650,000 audio files.

What data does it have?
AcousticBrainz contains information called audio features. This acoustic information describes the acoustic characteristics of music and includes low-level spectral information such as tempo, and additional high level descriptors for genres, moods, keys, scales and much more. These features are explained in more detail at http://acousticbrainz.org/sample-data

What can I do with it?
We hope that this database will spur the development of new music technology research and allow music hackers to create new and interesting recommendation and music discovery engines. Here are some ideas of things we would like to see:

Music discovery

Playlist generation

Improving the state of the art in genre recognition

Analytics on the musical structure of popular music

and more!

This is one of the largest datasets of this kind available for research, and the only one of this size that we know of which contains both freely available data as well as the reference source code used to compute the data.

How can I contribute?If you are a music researcher, you can help us by contributing to the essentia project. Go to the essentia homepage to see how you can do this. If you do something cool with the data let us know. We’d like to start a “made with AcousticBrainz” page where we will showcase interesting projects.

If you have any audio files, we would love for you to contribute audio features to our project. You can do this by downloading our submission clients from http://acousticbrainz.org/download. We provide clients for Windows, Mac, and Linux.